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Precision measurement instruments for machinery's mechanical compliance: design and operation

Measurement instruments for physics-based calibration of advanced manufacturing machinery

Time: Fri 2021-12-17 10.00

Location: F3, Lindstedtsvägen 26, Stockholm

Video link:

Language: English

Subject area: Production Engineering

Doctoral student: Nikolas Alexander Theissen , Industriell produktion

Opponent: Professor Alexander Slocum, Massachusetts Institute of Technology, U.S.A.

Supervisor: Professor Andreas Archenti, Design and Management of Manufacturing Systems, DMMS, Tillverkning och mätsystem, Hållbara produktionssystem, Processledning och hållbar produktion

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 Precision Measurement Instruments (PMIs) for machinery’s mechanical compliance are tools to quantify mechanical load as well as length for measurement ranges of 0.1 µm to 10 m at uncertainty levels of 0.1 µm to 100 µm while exerting mechanical loads. The quantity values of mechanical load and length can be used to identify compliance, which is a relationship describing mechanical loads to a change in geometry and vice versa. 

This work is based on and contributes to research in the field of quasi-static compliance measurements of machine tools and industrial robots. In this context, quasi-static means to experimentally measure as close as possible to the intended industrial use case, which results in the quantification of positioning accuracy un- der slow movements. These data can be utilised to gain an improved understanding of the machinery’s operational behaviour and via calibration, in combination with on- or off-line compensation, the performance of the machinery can be improved. This approach contradicts ISO standard recommendations for compliance measurements, as quasi-static measurements can be affected by several superimposed errors. The influence of these errors can be minimised through the design and operation of the PMI. Metrologists and engineers have defined precision engineering design principles to create accurate and precise PMI. Furthermore, the author has summarised complementary precision engineering operation principles of PMI to ensure reproducible compliance measurements under movement.

This doctoral thesis summarises and applies precision engineering design as well as operation principles to develop quasi-static compliance measurements through the Loaded Double Ball Bar - 3 Dimensional (LDBB-3D) and LDBB - 3 Dimensional Dynamic. These principles are exemplified in a case study on quasi-static elasto-geometric measurement of a machine tool by employing the designed LDBB- 3D. The results contribute to the understanding of the opportunities and limitations of PMI for experimental compliance measurements for model calibration and validation.